DESCRIPTION (Adapted from the application) The primary goal of this Clinical/Tissue Core is to provide tissues and serum from IBD patients to center investigators. The second goal of this core has been to establish a reference database of IBD patients and patient's samples for this center and nationally. This core has developed a customized database that is suitable to document the clinical and laboratory information of the entire IBD population at MGH. Through this database, it is easily to identify the desired patient subgroups and to provide clinical correlation and validation of tissue samples. During the previous funding period, the core service has been expanded to include development of a bank of serum and DNA samples from the IBD patient population. The core will provide the following services for center investigators; 1) clinical database and patient identification. The core will maintain an active clinical database of IBD patients. The investigators with the approved project have access to this database to identify patients needed for study; 2) tissue samples. The core is to provide tissue and serum for center investigator and to establish tissue and serum banks. Investigators needing tissue or serum samples contact the Core director or core technician after the director?s approval; 3) tissue reference bank. In addition to provision of fresh samples of IBD-related tissues and relevant controls, the core has been to store the validated tissue and serum samples for later study; 4) tissue sections. This service has made the core more effective in facilitating the goal of center investigators and make more maximal use of tissue samples; and 5) clinical support and biostatistical analysis. This core will provide the expertise in study design, data base management and analysis for clinical research.